Brake or the like frictionally engageable structure



Sept.' 14, 1948. w.` H. HUNTER 2,449,383

BRAKE 0R THE LIKE FRICTJQONALLY v ENGGEABLE S'I'RUCIUREf Filed 061", 28. 1943 fwwf@ y Patentedv Sept. 14, 1948 sl PATENT oEFlcE BRAKE R THE LIKE ERIC'rIoNALLY` ENQAGEABLE STRUCTURE Willson H. Hunter, Akron, Ohio, assigner to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application October 28, 1943, Serial No. 508,038

This invention relates to frictional mechanismsl for rota-table bodies, such as brakes for the wheels of aircraft or other vehicles, and features of the invention are useful also in other mechanisms such as clutches operated by fluid pressure.

The principal objects of the invention are to provide for dependable application of power, to provide efllciency of operation, to provide for facility of maintenance, to provideV a high degree of equalization inthe distribution of frictional pressure, toprovide protection of the expander tube against the effects of heat, to provide effective conforming action of the'frictlon surface, to provide an improved connection of the expander tube to a source of pressure. to

provide an improved construction and arrange- Fig. 2 is a cross-sectional view taken along the line 2, 2 of Fig. I showing the brake parts in an expanded condition.

Fig. 3 is a view like Fig. 2 but showing the brake parts in a retracted condition.

Fig.4 is a perspective view of parts of the brake.`

Fig. 5 is a partial cross-sectional view of another embodiment.

Fig. 6 is a clip spring adapted for use in the embodiment in Fig. 5.

Fig. 7 is a perspective view illustrating the construction of the torque flange of the embodiment of Fig.v 5. l

Referring to the drawings in the embodiment of the invention in Figs. 1 to 4, a torque frame I0 maybe fastened through holes II to a flange of a shaft (not shown). A rotatable brake drum I2 is located about the 'torque frame. The torque frame I0 is formed with a circumferential channel I3 which is defined by a fixed flange I5 at one side and a removable flange I4 at the other and fastened together by bolts I6. An annular expander tube I1 is seated within the channel I 3,with its inner face in continuous contact therewith, and is adapted to force a frictlonal surface against the drum I2 when the tube I1 is inated yby fluid pressure.

v To provide a fluid coupling between the ex, pander tube I'I and a source of fluid pressure, a

boss I9 is provided-in the torque frame having a local depression 20 with dished walls 2l to receive a rubber nozzle 22 of the expander tube I'I. A holek 23 is centrally located through the boss to the depression 20 at the inner periphery of the channel I3 to receive a hollow b olt 24. The bolt 24 has a tapered shoulder 25 to seat in a counter-sunk opening 26 of the hole 23. The diameter of the shankof the bolt 24 is `somewhat smaller than the hole 23 to provide an opening between the shank and the` hole 23. The bolt is closed at its lower end, except for radially extending apertures 24a. A hole 21 is provided in the boss I9 from the hole 23 to th-e outside wall of the boss to receive a connection pipe 28. By this arrangement of parts a communicating channel 29 is provided from the pipe 28, through the holes 2l, 23, 24a, and the hollow shank to the expander tube I1.

The expander tube I1 is provided with a spud 29a embedded in the rubber nozzle 22 and bonded thereto by vulcanization with a substantial layer of rubber 30 between the spud 29a and the shoulder face 3I of the boss, so that as the bolt 24 is admitted to the hole 23and turned into the spud 29a the layer of rubber 30 will be seated under compression and effect a fluid seal. at the bottom of the depression 20, while at the same time a fluid seal is effected between the bolt 24 and the boss I9 at the shoulder 25.

This assembly provides a fluid and air-tight seal with a minimum number of parts, provides a snug t of the nozzle into the recess provided in the torque frame, and provides a suitable tube anchorage against the frame, and at the same time leaves the nozzle somewhat flexible. This is desirable in that it provides some flexibility between the nozzle and the torque frame to allow minor displacement of the tube in the channel yas it expands and contracts during the operation p of the frictional mechanism.

Mounted in the channel I3 over the expander tube Il are a plurality of friction blocks 32 formed of heat-resistant frictional composition, and disposed circumferentially around the annular channel I3. 'These Vblocks 32 are adapted to lbe' forced into frictionable engagement with the drum I2 when the expander tube I1 is inflated by fluid pressure. To transmit torque from the blocks 32 to the torque frame Il), the blocks 32 are formed lwith their corners removed toreceive rectangular torque lugs 33 fastened as by rivets 34 to the top edge of the circumferential margins of the torque frame I6. The margins are provided. The blocks 32 are formed withl axially extending grooves 35 in their adjoining margins to receive the springs 36, each of which engages the radially inner wall of each of the opposing grooves of consecutive blocks 32 and bridges the space between the blocks entirely above the expander tube Il.

Each spring 36, in leaf form, is formed with a transverse arch 31 extending lengthwise of the spring preferably throughout*substantially the length of the grooves 35. The transverse arch is of such a shape as to have marginal flat areas 36 so that these areas 38 can contact the radially inner wall of each of the grooves 35 well into the groove. The spring 36 is more curved near its ends 39 beyond the transversely arched region than at such region so that while the more flat- When the pressure-'is released from the expander tened areas 38 are in continuous contact with the axial grooves the flexing ofthe spring 36 can occur most effectively near the ends 39 when the spring is under strain. By virtue of .this spring construction and arrangement, the friction blocks 32 move radially toward or away from the drum while maintaining substantial concentricity, so that as the expander tube applies pressure to the friction blocks, the pressure is transmitted equally over the areas of the blocks. and is equally relieved when pressure on Athe blocks is reduced. The ends 39 of the springs may be curved around toward the body of the spring and are so adapted to ride on the ramp 40 provided in a cavity 4I in the torque lugs 33 when the spring is ii'exed. The ramp surface 40 slopes toward the axis in the axially outward direction, which has the advantage that increased stiffness of the spring action is obtained as the sprinslides along the ramp dur'- ing braking action, and reduced tension on the spring is made possible at the start of its insertion into lugs 33, making for convenience in the assembly operations. KA recess 42 is provided in the margin of the torque lug so that under extreme radial movement of the parts the lugs will not interfere with the springs.

A thin metal insert I8 may be placed between the lower faces of the adjacent blocks32 and the expander tube I1 at the spaces as a further guard against radiated heat and further reduce the possibility of the expander tubes being locally deformed between the friction blocks 32. Thus the lugs 33 provide a m'eans of positioning the friction blocks 32 around the channel and also aI means of retaining the springs 36 in a torque free condition and the arrangement is such that a wide range of movement is made possible and thick blocks suitable for long wear may be utilized to advantage.

When pressure is applied to the expander tube I1 it engages the inner face of the friction blocks 32.- As the friction blocks 32 move radially outward toward the 'brake drum I2, the retractor springs 36 are displaced upward causing the ends 39 to ride along the ramp 46 provided in the cavity 4I on the torque frame I6. This spring action results in strong spring resistance without the use of objectionably stiff springs, and this stiffening action is provided at a time when such additional stiffness is needed, namely when the plurality of brake blocks reach their position of maximum radial expansion to contact the drum I2.

' is made for connecting theA leaf springs 50 to the torqueframe 5I by the use of C-clips .52 provided with curved ends 53 and 54 as shown in Figs. 5 and 6to engage respectively the curved end 55 of the leaf spring 56 and a beaded edge 56 of the torque frame 5I. l

U-shaped torque lugs 58 may be stamped or otherwise formed and extend inwardly at the outer periphery of the torque frame 5I so that a channel 59'lies beneath the lugs 58 to receive an expander tube 60.

In this arrangement the ends 55 of the retractor springs 50 may be displaced axially outward as radial pressure isdelivered onto the body of the springs, thus causing the C-clip 52 to pivot about the edge of the torque frame 5I, and making feasible a high degree of radial travel of the parts. This arrangement also facilitates instal 'lation and removal of the retractor springs without disturbing the other parts of the brake assembly.

Variations may be made without departing from the scope of the invention as it is defined by the following claims.

I claim;

1. A brake or the like frictionally engageable structure comprising a torque frame, an expander tube in said frame, a series of friction blocks at .a face of said tube, bowed retractor springs bearing on said blocks and extending axially across 1 said frame, and means on said frame for supporting the ends of said springs while accommodating 'change of lengthvof the springs during flexire thereof, the last said means comprising C-shaped elements hooked about the ends of said springs and about portions of said frame.

2. A frictionally engageable structure comprising a torque frame having cavitied torquelugs. an expander tube adjacent thereto, frictional blockshaving corners thereof recessed to receive said torque lugs' to prevent rotative movement of said blocks relative to said frame, said blocks having'grooves in the ends, retractor springs engaging walls of said grooves, said springs having longitudinally curled ends providing rounded bearing surfacesadapted to ride along walls of the cavities of said torque lugs as the springs are exed under the expansion and contraction of said expander tube.

3. A brake or like frictionally engageable structure comprising a torque frame provided with torque lugs and having an annular channel, an

annular expander tube in said channel, frictional elements having grooves in their ends and the ing on said blocks and extending axially across said frame, `said springs having curled ends providing rounded bearing surfaces, and means on said frame for supporting the curled ends of said springs while accomodating change of-length of the springs during exure thereof, said means 5. A brake or the like trictionally engageable structure comprising a torque frame, an expander tube in said frame, a series of friction blocks at a face of said tube, bowed retractor springs bearing on said blocks and extending axially across said frame, said springs having curled ends providing rounded bearing surfaces, and means lon said frame for supporting the curled ends of said springs while' accommodating change of length of the springs during iiexure thereof, said means comprising c-shaped elements hooked about the curled ends of said springs and about portions of said frame.

6. A brake or like frictionaliy engageable structure comprising a torque frame. a expander in said frame, a series of friction blocks at a face of said expander. bowed retractor springs bearing on said blocks and extending axially across said frame. said springs having ends curved longitudinally of the springs and relatively ilat crosswise thereof for bearing upon said torque frame tions for engaging said blocks, and means on said and having transversely arched intermediate porv tions relatively stin as compared to said end portorque 4frame for supporting the endsl of said springs. i

' WILLSON H. HUNTER. Y

REFERENCES CITED The following references are of record in the file of this patent:

f `UNITED STATES PATENTS Hollerlth May 30, 1944 

